P( sin t {\displaystyle \sin t\,\!} , cos t {\displaystyle \cos t\,\!} ) or P(x, y)
sin t = y {\displaystyle \sin t=y\,\!}
cos t = x {\displaystyle \cos t=x\,\!}
tan t = sin t cos t = y x {\displaystyle \tan t={\frac {\sin t}{\cos t}}={\frac {y}{x}}\,\!}
cot t = cos t tan t = x y {\displaystyle \cot t={\frac {\cos t}{\tan t}}={\frac {x}{y}}\,\!}
sec t = 1 cos t = 1 x {\displaystyle \sec t={\frac {1}{\cos t}}={\frac {1}{x}}\,\!}
csc t = 1 sin t = 1 y {\displaystyle \csc t={\frac {1}{\sin t}}={\frac {1}{y}}\,\!}
A function is periodic iff. f ( x + c ) = f ( x ) {\displaystyle f(x+c)=f(x)\,\!}
sin 2 x + cos 2 x = 1 {\displaystyle \sin ^{2}x+\cos ^{2}x=1\,\!}
1 + cot 2 x = csc 2 x {\displaystyle 1+\cot ^{2}x=\csc ^{2}x\,\!}
1 + tan 2 x = sec 2 x {\displaystyle 1+\tan ^{2}x=\sec ^{2}x\,\!}
, 
) or P(x, y)
